I think this is the link to the pattern. The 227sts is the entire sweater: button bands, fronts and back. You'll get to a point where you cast off the button band, pattern across 39sts to the armhole, cast off 6sts for the armhole, pattern across 99sts for the back, cast off 6sts for the armhole, pattern across the remaining sts (then you cast off the other button band on the next row). The 39sts and 99sts are just to let you know how many sts to work for the fronts and back.
So cast on 227sts and all will be well as you knit the body of the sweater up to the armholes. The buttonband cast off is a little unusual but it will work out fine when it joins with the picked up (knitted up) sts for the shawl collar.